Method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider

1. A method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, said method comprising: isolating a slider from ground; filtering a slider velocity signal to acquire a vibration signal; phase-shifting said vibration signal; adjusting an amplitude of said vibration signal to achieve an amplitude adjusted vibration signal; and applying said amplitude adjusted vibration signal to said slider to actively dampen air bearing vibrations in said slider.

2. The method of claim 1 further comprising: adding a DC (direct current) offset to said vibration signal.

3. The method of claim 1 wherein said filtering a slider velocity signal to acquire a vibration signal comprises filtering said slider velocity signal through a high pass filter and keeping the portion of said signal that is above approximately 50 kHz in frequency.

4. The method of claim 1 wherein said filtering a slider velocity signal to acquire a vibration signal comprises filtering said slider velocity signal through a band pass filter and keeping the portion of said signal that is between approximately 50 kHz in frequency and approximately 500 kHz in frequency.

5. The method of claim 1 wherein said filtering a slider velocity signal to acquire a vibration signal comprises filtering slider velocity signal through a band pass filter and keeping the portion of said signal that substantially encompasses the air bearing pitch two mode frequency range of said slider.

6. The method of claim 1 wherein said adjusting said amplitude of said vibration signal comprises adjusting said amplitude of said vibration signal with a variable gain amplifier.

7. A method of feedback control for active damping of slider air bearing vibrations in a hard disk drive slider, said method comprising: providing a slider, wherein said slider is isolated from ground; providing a filter capable of filtering a slider velocity signal to acquire a vibration signal; providing a phase-shifter capable of phase-shifting said vibration signal; providing an amplifier capable of adjusting an amplitude of said vibration signal to achieve an amplitude adjusted vibration signal; and providing an electrical coupling to allow said amplitude adjusted vibration signal to be applied to said slider to actively dampen air bearing vibrations in said slider.

8. The method of claim 7 further comprising: providing a DC (direct current) voltage source capable of adding a DC offset to said vibration signal.

9. The method of claim 7 wherein said providing a filter capable of filtering a slider velocity signal to acquire a vibration signal comprises providing a filter capable of filtering said slider velocity signal through a high pass filter and keeping the portion of said signal that is above approximately 50 kHz in frequency.

10. The method of claim 7 wherein said providing a filter capable of filtering a slider velocity signal to acquire a vibration signal comprises providing a filter capable of filtering said slider velocity signal through a band pass filter and keeping the portion of said signal that is between approximately 50 kHz in frequency and approximately 500 kHz in frequency.

11. The method of claim 7 wherein said providing a filter capable of filtering a slider velocity signal to acquire a vibration signal comprises providing a filter capable of filtering said slider velocity signal through a band pass filter and keeping the portion of said signal that substantially encompasses the air bearing pitch two mode frequency range of said slider.

12. The method of claim 7 wherein said providing an amplifier capable of adjusting said amplitude of said vibration signal comprises providing a variable gain amplifier capable of adjusting said amplitude of said vibration signal.